مجله تولیدات دامی
سال بیست و هفتم شماره 1 (بهار 1404)

Identifying selection signatures  can provide valuable insights into genomic regions that are under positive selection, which in turn leads to a better understanding of genotype-phenotype relationships Over the past few decades,, selection programs in broiler chicken have been based on fast growing and increased feed efficiency. On the other hand, this selection for rapid growth has been resulted an accumulation of fatty tissue and decrease of chicken meat quality, it has been new challenges in poultry breeding due to genetic correlation between rapid growing and fat deposition. The aim of the present study was to identify genomic regions under positive selection associated with body fat deposition in seven-week-old broiler chickens  using a statistical method based on linkage disequilibrium.

In the present study, a total 475 chickens from two chicken lines divergently selected were obtained using the Illumina chicken 60 K SNP chip. The broilers used in this study were from two Chinese broiler lines. In the first step, for the detected regions of the genome were evaluated using the XP-EHH method based on linkage disequilibrium using Selscan software v.2.0. Candidate genomic regions and genes were identified by SNPs located at 1% upper range of XP-EHH values in ten creeping windows. Finally, GeneCards and DAVID databases were also used to interpret the function of the obtained genes. Additionally, the latest published version of Animal genome database was used for defining QTLs associated with fat deposition traits in identified locations.

Candidate genes STAB2, TAPT1, JDP2, FNDC3B, PTPN11, ADIPOR1 and SLC44A3 obtained these regions. Further investigation using bioinformatics tools showed these genomic regions overlapped with lipid metabolism, fatty acid transport, lipoprotein receptors, glucose metabolism and homeostasis. Various genes that were founded within these regions can be considered as candidates under selection based on function. Also, a survey on extracted QTLs showed that these QTLs involved in some economically important traits in chicken such as abdominal fat weight and carcass fat weight traits.

However, will be necessary to carry out more association and functional studies to demonstrate the implication of genes obtained from association analyses. Identifying important economic traits and locating parts of the genome that have changed as a result of selection could be used in poultry breeding programs. The results of our research can be used to understand the genetic mechanism controlling fat deposition trait and using these findings could potentially be useful for genetic selection in chicken for increasing body weight while reducing body fat deposition during a broiler breeding.

Proper raising of suckling calves is important in creating a profitable productive herd. In this regard, the three important principles of nutrition, preservation of the environment and disease control will be effective in reducing losses caused by losses from birth to weaning. In recent years, efforts have been made in calf nutrition to find the best combination of starter diets to justify the best growth and health. Grain processing makes starch available to microbes and increases the rate and extent of starch degradation in the rumen. Considering that there is little information about the effect of barley processing on feed intake and performance behavior in dairy calves, therefore, this study aims to compare non-steamed flaked barley with milled barley on performance, fecal score, chewing behavior and blood parameters of Holstein suckling calves.

In this study, 12 Holstein female calves aged 20 to 25 days and an initial body weight of 44±2.7 kg were used in two treatments and six replications. The treatments included: 1- starter diet containing milled barley, and 2- starter diet containing non-steamed flaked barley. The duration of the trial period was 35 days. The experimental diets were isoenergetic and isonitrogenous. On the 58th and 59th days of the experiment, feed intake behavior was calculated by recording activity for 24 hours. During the research period, the calf fecal score was also checked. To measure blood parameters on the 35th day of the experiment, blood was taken four hours after morning feeding using heparinized venoject tubes from the jugular vein of the calves.

The results comparing the effect of milled and non-steamed flaked barley on the performance of Holstein calves showed that there is a significant difference between the calves fed non-steamed flaked barley in terms of final weight, weight changes, average daily gain (ADG), dry matter intake (DMI) and feed conversion ratio (FCR) than calves fed milled barley (P<0.05). The calves fed non-steamed flaked barley had more weight changes (11.66) during the experimental period. There was a significant difference in eating behavior, rumination, chewing and rest of calves between experimental treatments (P<0.05). The fecal consistency score, the number of calves with diarrhea and the average days with diarrhea were not affected by the treatments Blood glucose concentration of calves fed non-steamed flaked barley was higher than that of calves consumed milled barley (P<0.05). However, blood concentrations of triglyceride, cholesterol, urea, total protein, albumin, globulin and their ratio were not affected.

The results of the present study showed that the use of non-steamed flaked barley compared to milled barley increased DMI and ADG, and improved FCR and eating behavior of dairy calves.

The various challenges that cows face in late pregnancy have lasting effects, affecting aspects of the calf's metabolism at birth and post-colostrum immunity. On the other hand, the increase in oxidative stress and excessive production of free radicals during the transfer period affects the growing fetus. This effect can alter the ability of calves to defend themselves against pathogens and cope with stressors, leading to changes in body weight, performance and skeletal development during the critical first month of life. Identifying and optimizing the effect of specific nutrients in the animal health program can be an efficient management strategy to reduce oxidative stress and inflammation associated with the transition period, followed by immune disorders and impaired health and growth of calves; In this regard, vitamins and minerals are known for their anti-inflammatory and anti-oxidative properties. Providing essential micronutrients to the mother during pregnancy is an effective way to meet the needs of the baby.

This experiment was conducted in order to investigate the effect of injecting minerals and vitamins in the late pregnancy of cows on performance, stool consistency, some blood metabolites, antioxidant status and skeletal growth indicators of their calves. For this purpose, 32 pregnant cows were selected based on the calving cycle, age, body weight and body condition score and were divided into 4 treatments and 8 repetitions in the form of a completely randomized design. Experimental treatments included: 1) control group (no vitamin and mineral supplement injection), 2) treatment receiving injectable vitamin supplement, 3) treatment receiving injectable mineral supplement and 4) treatment receiving vitamin and mineral supplement injection together. Supplements were injected 28 days before calving. After birth, calves born from each group were examined for 35 days. Blood samples were taken from calves at the end of the ex-perimental period (35 days after birth) to measure blood parameters.

The results showed that birth weight, day 35 weight, daily weight gain and total dry matter consumption of calves born from mothers receiving minerals, vitamins and minerals and vitamins were increased compared to the control group (P≥0.05). In the treatments receiving minerals, vitamins, and minerals and vitamins, an increase in colostrum IgG, IgG consumed by each calf, and serum IgG of calves was observed at birth and three days after birth (P≥0.05). Also, maternal injection of minerals and vitamins improved stool consistency and reduced the number of animals suffering from diarrhea; So that the best result was obtained from the simultaneous injection of minerals and vitamins (P≥0.05). On the other hand, the concentration of glucose, total protein and albumin of calves receiving maternal minerals, vitamins and minerals and vitamins were associated with a significant change compared to the control treatment (P≥0.05). Maternal injection increased the activity of glutathione peroxidase and decreased the total antioxidant status in calves compared to control calves (P≥0.05). The superoxide dismutase enzyme activity of calves born from the group receiving minerals and vitamins at the same time was associated with an increase, and the highest change in catalase activity was related to calves receiving treatment of minerals, and minerals and vitamins. In the calves born from the treatments receiving minerals, vitamins and minerals and vitamins, the height of the withers on the 28st day was increased compared to the control calves (P≥0.05).

In general, the simultaneous injection of minerals and vitamins to animals in the transition period before calving is recommended due to better performance and improvement of the immune system and health of their calves.

The physical characteristics and nutrient balance of feed are among the most critical factors influencing animal health, performance, and feeding behavior of livestock. These factors not only have a direct impact on meeting the nutritional requirements of livestock but also play a key role in enhancing production efficiency, improving product quality, and mitigating nutrition-related diseases. This study aimed to evaluate the effects of feed physical form during late gestation and early lactation in ewes on blood metabolites, antioxidant status, and lamb performance after birth.

This study was conducted using 36 Mehraban breed ewes with an average body weight of 50.17±2.09 kg and an average age of three to four years in a completely randomized experimental design. The experimental treatments included: 1- mash concentrate, 2- pelleted concentrate, and 3- pelleted total mixed ration (TMR). Experimental treatments were provided to ewes during the last two months of pregnancy and the first month of lactation. To evaluate blood biochemical parameters and antioxidant status, blood samples were collected from the ewes at three times (30 days before lambing, day of lambing, and 30 days after lambing) before the morning feeding. Milk yield and milk fat content were also assessed on day 21 postpartum. Also, the performance of the lambs was evaluated by weighing them on the day of birth and weekly until the end of the trial.

The results indicated that feed intake during in the pre- and post-partum periods, as well as milk production, was higher in ewes fed with pelleted TMR and pelleted concentrate compared to those fed with mash concentrate (P<0.05), while the milk fat percentage was not affected by the experimental treatments. Feeding pelleted TMR and pelleted concentrate significantly increased serum glucose and urea concentrations (P<0.05), while other blood parameters, such as cholesterol, triglycerides, total protein, and liver enzymes, were not influenced by the experimental treatments. Also, feeding ewes with pelleted feed led to a significant reduction in malondialdehyde concentration and an increase in total antioxidant capacity at certain time points (P < 0.05), indicating a reduction in oxidative stress in animals fed this type of feed. In addition, body weight and daily weight gain of lambs were affected by the physical form of the feed consumed by the ewes at certain time points. Lambs born to ewes fed with pelleted TMR and pelleted concentrate had higher weight and daily weight gain between days seven and 30 of age than those born to ewes fed with mash concentrate (P<0.05). However, no significant difference was observed in lamb birth weight between different treatments.

Overall, the results of this study indicated that feeding ewes with pelleted TMR and pelleted concentrate during late pregnancy and early lactation can improve ewe performance, improve lamb performance, increase certain biochemical parameters, and enhance the antioxidant status of the ewes' blood. These findings emphasize the effective role of the physical form of feed as an effective tool in optimizing animal health, production performance, and welfare.

The use of probiotics and medicinal plants as growth promoters and alternatives to antibiotics in the diet of broiler chickens leads to the prevention of the the growth of harmful intestinal bacteria, including coliforms, increased resistance to pathogens, promotes the synthesis of antioxidants and antibacterials, stimulates local immunity, and improves immune system function. Therefore, this study aimed to investigate the effect of adding sea galangal (Alpinia officinarum) powder and probiotics on growth performance, carcass characteristics, blood cell population, caecal bacterial population, and ileum tissue morphology of Japanese quail under heat stress conditions

The experiment was conducted using 480 quail chicks in a completely randomized design with 24 experimental units, six treatments, and four replications. Experimental treatments included: 1- Control (basal diet without galangal powder or probiotics); 2- Basal diet with 50 mg of galangal powder; 3- Basal diet with 100 mg of galangal powder; 4- Basal diet with 50 mg of galangal powder+ 0.2 g/kg lactofeed probiotic; 5- Basal diet with 100 mg of galangal powder+ 0.2 g/kg lactofeed probiotic; 6- Basal diet with 0.2 g/kg lactofeed probiotic only. Performance traits (weight gain, feed intake, and feed conversion ratio) of quail chicks were evaluated at 10, 20, and 35 days of age and over the whole period. Carcass characteristics, blood cells, caecal bacterial populations, and ileum tissue morphology were also assessed.

The use of galangal powder and probiotics significantly improved feed intake and feed conversion ratio under heat stress conditions. Carcass yield was higher in quail that received galangal powder + probiotics (P<0.05). The heterophil level and heterophil-to-lymphocyte ratio and lymphocytes count in quail fed diets containing galangal powder and probiotics were lower than in the control group under heat stress conditions (P<0.05). The population of lactic acid bacteria in the cecum of birds fed diets containing galangal powder and probiotics was higher than in other treatments (P<0.05). Under heat stress conditions, the total bacterial population and the population of cecum coliforms were higher in the control treatment than in other experimental groups. Villus height, crypt thickness, and the villus height-to-crypt depth ratio in the ileum tissue were higher in birds fed 50 mg of galangal powder+ 0.2 g/kg probiotic than in the control treatment under heat stress conditions (P<0.05); while the highest crypt depth was observed in birds fed the control treatment. The parameters of crypt diameter, inner and outer muscle layer thickness of ileum tissue were not affected by any of the experimental treatments under heat stress conditions.

In conclusion, adding 50 mg of sea galangal powder + 0.2 g/kg lactofeed probiotics to the basal diet under heat stress conditions significantly improved carcass yield, caecal bacterial population, blood cell counts, and ileum tissue morphology of Japanese quail.

Optimizing the balance between metabolizable energy (ME) intake and expenditure is essential for broiler diet formulation and levels of other dietary nutrients for efficient conversion of feed into muscle mass. The Arian broiler is one of the meat breeds that originated in Iran and given that several decades have passed since the Arian line entered in the Iran; it is necessary to conduct continuous nutritional experiments to more accurately estimate their requirements in terms of improving growth, feed conversion ratio (FCR), carcass efficiency and increasing muscle mass by increasing the density of nutrients such as amino acids (AA). Therefore, the objective of this study was to investigate the effects of dietary energy and AA levels on growth performance and nutrient digestibility of Arian broilers.

The effects of dietary energy and AA levels  on growth performance and nutrient digestibility of Arian broiler chickens was investigated with a total of 720 one-day old broiler chicks in a completely randomized design with six treatments, five replicates and 24 birds per each for 42 days. The experimental treatments included T1:control diet (energy and amino acid levels throughout the breeding period accordance with the guidelines for the Arian broiler strain), T2:diet with less energy level during the starter and grower periods and then according to the Arian requairements guide until the end of the period, T3:diet with less energy and amino acid levels during the starter and grower periods and then according to the guide until the end of the period, T4:diet with less energy level during the starter and grower periods and then higher amino acid levels in the finisher period, T5:diet with less energy and amino acid levels in the starter and grower periods and then higher amino acid levels in the finisher period, T6:starter and grower period diet according to the Arian requairements guide and then higher amino acid levels in the finisher period.

The daily weight gain of birds fed T6 increased compared to T3 and T5 (P<0.05). Birds that received T6 had a higher glucose level and lower low-density lipoprotein, compared to the birds that received the control diet (P<0.05). The relative breast weight and production index of birds that were fed T6 increased compared to the birds that fed T1 and T3 (P<0.05).

The economic calculations of the design showed that it is possible to use the advantage of the energy and amino acid levels in the diet of Arian broilers. Overall, feeding a starter and grower period diet according to the Arian requairements guide and then higher amino acid levels in the finisher period which had positive effects on growth performance and economic indicators in Arian broilers, is recommended.

The present study aimed to investigate the effects of organic and inorganic forms of copper, zinc, and manganese on broiler breeder hens' productive and reproductive performance of Ross 308 broiler breeders at 33 and 36 weeks.

In this study, 240 hens and 30 roosters of Ross 308 strain were used in 30 experimental pens. This research was carried out as a factorial experiment 2×3 with three types of minerals (copper, zinc, and manganese) and two forms (organic and inorganic) in a completely randomized design with six treatments, five replications, and 8 hens and one rooster in each replication. Weeks 29 to 32 were considered as the adaptation period. The experimental treatments included: 1) diet containing inorganic zinc, 2) diet containing organic zinc, 3) diet containing inorganic copper, 4) diet containing organic copper, 5) diet containing inorganic manganese, and 6) diet containing organic manganese. The required amount of elements in inorganic form was 16 mg/kg for copper (copper sulfate), 90 mg/kg for zinc (zinc sulfate) and 130 mg/kg for manganese (manganese sulfate) and the recommended amount of elements in organic form in the present study was 13.33 mg/kg for copper (copper-methionine), 48.65 mg/kg for zinc (zinc-methionine) and 73.86 mg/kg for manganese (manganese-methionine). The data obtained by LSmeans method were analyzed by SAS statistical software.

The results indicated that the use of diets containing organic forms of elements had a significant effect  on egg production traits, including egg production rate, egg mass, egg weight, hatchable eggs, fertility rate, hatchability, and the weight of hatched chicks (P< 0.05). Specifically, organic zinc enhanced the percentage of egg production, egg weight, and egg mass during weeks 33 and 36 of the study. However, inorganic zinc demonstrated a better effect on egg mass compared to inorganic manganese (P< 0.05). Furthermore, the effect of organic and inorganic copper, as well as inorganic zinc, on the percentage of egg production in these weeks was significantly greater than that of inorganic manganese (P< 0.05). Similarly, regarding egg weight, a significant positive effect was observed from the combination of organic copper and inorganic zinc, which performed better than inorganic copper and organic and inorganic manganese (P< 0.05). The results also revealed that the effect of organic zinc on the percentage of hatchable eggs was significantly greater than that of other organic and inorganic elements among the treatments in the  weeks studied (P< 0.05). In addition, the findings regarding hatchability indicated that the effects of both organic and inorganic zinc surpassed those of other elements (P< 0.05). The influence of these elements on the fertility rate was also significant, with organic and inorganic zinc exhibiting a higher effect than other organic and inorganic elements (P< 0.05). Lastly, the impact of the studied elements on the weight of freshly hatched chicks demonstrated the superiority of organic zinc compared to other organic and inorganic elements.

In general, the effect of organic form of elements on the studied traits was greater than the inorganic form of elements, and the highest and lowest effect of the treatments on the studied traits were related to organic zinc and inorganic manganese, respectively. Based on the present results, the use of organic forms of elements (especially organic zinc) is recommended to improve the production and reproductive traits of broiler breeders.

Due to the development of resistance to common anthelmintic drugs, researchers are looking for efficient and cost-effective ways to combat parasitic infections. Nanoparticles are currently being used for biomedical applications due to their nanoscale size and high reactivity. Given the high prevalence of trichostrongylosis in small ruminants, any disruption in the development of the proparasitic stages can play an important role in the control and prevention of the disease. Nanoparticles, as a new, safe, cheap and available antiparasitic agent, can play an important role in reducing the incidence of gastrointestinal strongylosis in ruminants.

A number of sheep feces samples were collected directly from the rectum of the animal and examined for parasitic infections with Strongyloides eggs using the fecal flotation method. Then, feces culture was performed on samples infected with Strongyloides eggs under appropriate temperature and humidity conditions for seven to 10 days. After 24 to 48 hours of cultivation, the first and second stage (L1 and L2) trichostrongylid larvae in the culture medium were collected using the Berman method and exposed to metal nanoparticle oxides such as aluminum, zinc, and iron in combination with 5% dimethyl sulfoxide (DMSO) and once without DMSO. Also, the third stage (L3) trichostrongylid larvae were exposed to these nanoparticles after stool culture and isolation using the Berman method. Then, the mortality rate of each larva was examined and counted under a stereomicroscope according to their movement. Distilled water and albendazole were used as negative and positive controls of the experiments, respectively. In order to examine the ultrastructural surface of the larvae cuticle treated with nanoparticles, a number of L3 trichostrongylid larvae were prepared before exposure to nanoparticles and after exposure using a scanning electron microscope (SEM).

The real mortality rates of L1 and L2 larvae treated with aluminum oxide at concentrations of 0.02, 0.04, and 0.06 mg/ml were 23.9, 44.66, and 70.85%, respectively, zinc oxide were 43.03, 51.30, and 95.92%, respectively, and iron oxide were 84.33, 42.96, and 48.98%, respectively. No mortality was observed in the treatment group exposed to metal nanoparticles in L3 larvae. In the scanning electron microscope images were observed the cuticular layer of L1 and L2 trichostrongylid larvae treated with iron oxide nanoparticles had a rough and wrinkled appearance compared to the smooth and uniform appearance of the normal larvae.

Based on the resultsy, and considering the low price and availability of iron and zinc nanoparticles, they can be widely used as a preventive agent against trichostrongylosis in small ruminants in pastures.